The Coronal Abundances of Mid-F Dwarfs

Abstract

A Chandra spectrum of the moderately active nearby F6 V star Pi3 Ori is used to study the coronal properties of mid-F dwarfs. We find that Pi3 Ori's coronal emission measure distribution is very similar to those of moderately active G and K dwarfs, with an emission measure peak near $\log T=6.6$ seeming to be ubiquitous for such stars. In contrast to coronal temperature, coronal abundances are known to depend on spectral type for main sequence stars. Based on this previously known relation, we expected Pi3 Ori's corona to exhibit an extremely strong "FIP effect," a phenomenon first identified on the Sun where elements with low "First Ionization Potential" (FIP) are enhanced in the corona. We instead find that Pi3 Ori's corona exhibits a FIP effect essentially identical to that of the Sun and other early G dwarfs, perhaps indicating that the increase in FIP bias towards earlier spectral types stops or at least slows for F stars. We find that Pi3 Ori's coronal characteristics are significantly different from two previously studied mid-F stars, Procyon (F5 IV-V) and Tau Boo (F7 V). We believe Pi3 Ori is more representative of the coronal characteristics of mid-F dwarfs, with Procyon being different because of luminosity class, and Tau Boo being different because of the effects of one of two close companions, one stellar (Tau Boo B: M2 V) and one planetary.

to appear in The Astrophysical Journal

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Cited by in corpus (10)

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• A Chandra/LETGS Survey of Main Sequence Stars
• A Solar cycle correlation of coronal element abundances in Sun-as-a-star observations
• Ponderomotive Acceleration in Coronal Loops
• Extending the FIP bias sample to magnetically active stars. Challenging the FIP bias paradigm?
• The Factory and the Beehive. IV. A Comprehensive Study of the Rotation X-ray Activity Relation in Praesepe and the Hyades
• Coronae of Stars with Super Solar Elemental Abundances
• Reflection of fast magnetosonic waves near magnetic reconnection region
• Chandra Characterization of X-ray Emission in the Young F-Star Binary System HD 113766